Pressure compensated solenoid valve with fluid flow force balancing

ABSTRACT

A pressure compensated solenoid valve with fluid flow force balancing is provided. The solenoid valve includes an armature and a valve plunger arranged to transport hydraulic fluid from a supply end of a valve plunger to an upper end of the armature facilitating a resultant upper fluid force that acts upon the upper end of the armature to balance a resultant lower fluid force that acts on the supply end of the valve plunger. The solenoid valve includes a poppet that is configured as a pressure-relief valve for maintaining a minimum fluid pressure within an actuation fluid gallery. An inlet fluid force of the poppet is balanced by an outlet fluid force of the poppet.

TECHNICAL FIELD

Example aspects described herein relate to solenoid valves, and, moreparticularly, to solenoid valves used in variable valve lift or variablevalve timing systems of internal combustion engines for automobiles.

BACKGROUND

Variable valve lift (VVL) and variable valve timing (VVT) systems ofinternal combustion (IC) engines often manage hydraulic fluid flow,leakage or pressure within a network of fluid galleries to vary theoutput of these respective systems. This type of hydraulic fluidmanagement is typically handled by a solenoid valve which can beprecisely controlled by an electronic controller such as an enginecontrol unit (ECU). A solenoid valve that consistently functionsthroughout the varying operating conditions of the IC engine is criticalto the accuracy and performance of many VVL and VVT systems.

SUMMARY OF THE INVENTION

A pressure compensated solenoid valve with fluid flow force balancing isprovided. The solenoid valve includes a central axis, a bobbinconfigured to support a coil, a pole, a containment tube, an armature, avalve plunger, and a poppet. The coil is configured to produce amagnetic field when energized with electric current. At least a portionof the pole is circumferentially surrounded by the bobbin; at least aportion of the containment tube is circumferentially surrounded by thepole; and, at least a portion of the armature is circumferentiallysurrounded by the containment tube. The armature is configured to beaxially displaceable by the magnetic field. The valve plunger is axiallydisplaceable within the valve housing to a first seated position or asecond non-seated position. The first seated position can correspondwith a de-energized state of the coil, and the second non-seatedposition can correspond with an energized state of the coil. In anexample embodiment, while in the first seated position, an actuationport of the solenoid valve is not fluidly connected to a fluid supplyport of the solenoid valve, and while in the second non-seated position,the actuation port of the solenoid valve is fluidly connected to thefluid supply port of the solenoid valve.

The poppet is arranged to be axially displaceable within the valvehousing to a first closed position or a second pressure-relief position.The poppet is biased to the first closed position by a poppet biasspring. In the first closed position, the poppet can engage an upperlanding surface of the valve plunger. In the second pressure-reliefposition, the poppet can be configured to fluidly connect an actuationport of the solenoid valve to a tank port of the solenoid valve.

At least a portion of the valve plunger can extend through athrough-passage of the poppet. The valve plunger can be configured witha first fluid flow passage and the armature can be configured with asecond fluid flow path that is fluidly connected to the first flow path.The first and second fluid flow paths can be arranged to transporthydraulic fluid from a supply end of the valve plunger to an upper endof the armature such that a resultant upper fluid force acting on theupper end of the armature is balanced by a resultant lower fluid forceacting on the supply end of the valve plunger.

The poppet is arranged with a first surface at a first end and a secondsurface at a second end, the first and second surfaces are configured toequalize, respectively, an inlet fluid force acting on the poppet withan exiting fluid force acting on the poppet, with the poppet in thesecond pressure-relief position. The poppet bias spring and at least aportion of the first surface can cooperate to define a cracking pressureof the poppet. The poppet can be configured with a lower spring well toreceive at least a portion of the poppet bias spring.

The poppet can be configured to be engaged at a first angled end by aninlet fluid that produces an inlet fluid force, and at a second angledend by an exiting fluid producing an exiting fluid force; the poppet canbe balanced by the incoming fluid force and the exiting fluid forcewhile in the second pressure-relief position.

The first surface of the poppet and the upper landing surface of thevalve plunger can form a fluid access gap that is configured to receivea fluid; the poppet can be configured to be axially displaceable by thefluid within the fluid access gap.

The upper landing surface of the valve plunger can define a third angledsurface having a third angle. The first surface of the poppet can definea first angled surface having a first angle, and the first angle can bedifferent than the third angle. The first angled surface and the thirdangled surface can form a fluid access gap.

In an example embodiment, the solenoid valve can further include anarmature bias spring arranged between the armature and the containmenttube, with the armature bias spring urging the valve plunger to thefirst seated position. At least a portion of the armature bias springcan be received by a spring bore arranged on an upper end of thearmature.

In an example embodiment, the solenoid valve can further include asealing collar that is arranged within the valve housing, and at least aportion of the valve plunger can extend through the sealing collar. Thesealing collar can be configured as a longitudinal stop for the poppetin the second pressure-relief position. Furthermore, the sealing collarcan be configured with an upper spring well that receives at least aportion of the poppet bias spring.

In an example embodiment the valve plunger can include a fluid apertureconfigured to fluidly connect a fluid supply port of the solenoid valveto an actuation port of the solenoid valve while in the first seatedposition or the second non-seated position.

BRIEF DESCRIPTION OF DRAWINGS

The above mentioned and other features and advantages of the embodimentsdescribed herein, and the manner of attaining them, will become apparentand be better understood by reference to the following descriptions ofmultiple example embodiments in conjunction with the accompanyingdrawings. A brief description of the drawings now follows.

FIG. 1 is a perspective view of an example embodiment of apressure-compensated solenoid valve with fluid flow force balancing,together with an electronic controller.

FIG. 2A is a first perspective view of an example embodiment of aflow-balanced poppet.

FIG. 2B is a second perspective view of the poppet shown in FIG. 2A.

FIG. 3A is a first cross-sectional view taken from FIG. 2A.

FIG. 3B is a second cross-sectional view taken from FIG. 2A.

FIG. 4A is a cross-sectional view of the solenoid valve of FIG. 1.

FIG. 4B is a detailed view taken from FIG. 4A.

FIG. 5A is a partial cross-sectional view of the solenoid valve of FIG.1, showing a first seated position of a valve plunger and a first closedposition of the poppet.

FIG. 5B is a partial cross-sectional view of the solenoid valve of FIG.1, showing a first seated position of the valve plunger and a secondpressure-relief position of the poppet.

FIG. 5C is a partial cross-sectional view of the solenoid valve of FIG.1, showing a second non-seated position of the valve plunger.

FIG. 6 is a perspective view of an example embodiment of a valveplunger.

FIG. 7 is a cross-sectional view of an example embodiment of apressure-compensated solenoid valve with fluid flow force balancing.

FIG. 8A is a schematic of a fluid inlet passage between the poppet andvalve plunger shown in FIG. 5B.

FIG. 8B is a schematic of a fluid exit passage between the poppet andvalve plunger shown in FIG. 5B.

DETAILED DESCRIPTION OF THE INVENTION

Identically labeled elements appearing in different figures refer to thesame elements but may not be referenced in the description for allfigures. The exemplification set out herein illustrates embodimentswhich should not be construed as limiting the scope of the claims in anymanner. A radially inward direction is from an outer radial surface,toward the central axis or radial center of the component. Conversely, aradial outward direction indicates the direction from the central axisor radial center of the component toward the outer surface. Axiallyrefers to directions along a diametric central axis. The words “upper”,“lower”, “upward”, “downward”, “above” and “below” designate directionsin the drawings to which reference was made.

Referring to FIG. 1, a perspective view of an example embodiment of apressure compensated solenoid valve 10 with fluid flow force balancingis shown. FIGS. 2A and 2B show perspective views of an exampleembodiment of a flow-balanced poppet 50 that is arranged within thesolenoid valve 10 of FIG. 1. FIGS. 3A and 3B show cross-sectional viewstaken from the poppet 50 of FIG. 2A. FIG. 4A shows a cross-sectionalview taken from the solenoid valve 10 of FIG. 1. FIG. 4B shows anenlarged cross-sectional view taken from the cross-sectional view ofFIG. 4A, showing upper and lower fluid forces UFF, LFF acting on anarmature 28 and a valve plunger 70, respectively; and, inlet and exitingflow forces IFF, EFF acting on first and second respective ends 52, 56of the poppet 50. FIGS. 5A through 5C show different positions of thevalve plunger 70 and poppet 50 and corresponding fluid galleryconnections. FIG. 6 shows a perspective view of an example embodiment ofa valve plunger 70 for the solenoid valve 10 of FIG. 1. The followingdiscussion should be read in light of FIGS. 1 through 6.

The solenoid valve 10 includes a central axis 12, and a bobbin 21 thatradially houses and supports a coil 26. A yoke 18 is arranged at a topportion of the bobbin 21. The coil 26 becomes energized when it receiveselectric current via an electric terminal 14. The control and selectivedelivery of the electric current is managed by an electronic controller19 that powers the solenoid valve 10. The electric terminal 14 is housedby a plastic overmold 16. The presence of electric current in the coil26 induces a magnetic field which causes the armature 28 to move axiallydownward within a containment tube 34 that circumferentially surroundsthe armature 28. The containment tube 34, or at least a portion thereof,is circumferentially surrounded by a pole 36. The pole 36 includes anupper pole tube 24 and a lower pole ring 25, however, a one-piece designis also possible, as shown in FIG. 7. The pole 36, or at least a portionthereof, is circumferentially surrounded by the bobbin 21. A lower end31 of the armature 28 engages with an upper end 77 of the valve plunger70. A coupling (not shown) may be added that connects the armature 28 tothe valve plunger 70. The valve plunger 70 is axially displaceablewithin a valve housing 44. A solenoid housing 20 circumferentiallysurrounds the coil 26 with a bottom end 23 of the solenoid housing 20securing a mounting tab 40 to a solenoid end 43 of the valve housing 44.A supply end 76 of the valve plunger 70 is configured with a lowerseating surface 73 that can engage or abut with a receiving land 74formed within a central aperture 45 of the valve housing 44. A portionof the valve plunger 70 extends through a clearance aperture 48 of asealing collar 42, with the sealing collar 42 arranged at a solenoid end43 of the valve housing 44 and forming an exit fluid passage with thepoppet 50. The sealing collar 42 includes an upper spring well 49 thatreceives a poppet bias spring 46, the upper spring well 49 including anupper spring land 47 to receive a top end of the poppet bias spring 46.Other design configurations for the valve plunger 70, sealing collar 42,and their associated interfaces, are possible.

A coil-de-energized state can yield a first seated position of the valveplunger 70, as shown in FIGS. 4A and 4B. In the first seated position,an armature return spring 22 urges the armature 28 in a downwarddirection with a first biasing force FS1 such that the lower seatingsurface 73 of valve plunger 70 is forcibly engaged with the receivingland 74 of the valve housing 44. This first seated position of the valveplunger 70 prevents a fluid connection between a fluid supply port 84and an actuation port 82 of the solenoid valve 10. The armature returnspring 22 is received within an armature spring well 32 located at anupper end 29 of the armature 28, however, any location of the armaturereturn spring 22 or any other force generator, for that matter, ispossible, to provide a seating force on the armature 28.

A coil-energized state can yield a second non-seated position of thevalve plunger 70, as shown in FIG. 5C. In this second non-seatedposition, a magnetic field created by the coil 26 overcomes the firstbiasing force FS1 of the armature return spring 22 and moves thearmature 28 and valve plunger 70 upward, facilitating a fluid connectionbetween the fluid supply port 84 and the actuation port 82 of thesolenoid valve 10. This actuation arrangement of the solenoid valve 10could also be described as a “pull-type” design, where energization ofthe coil 26 creates a magnetic field that pulls the armature 28 andvalve plunger 70 upward.

For many state of the art solenoid valves, a switching time of thesolenoid valve can vary with a changing hydraulic fluid supply pressure.Switching time can encompass the time it takes for an electronic signalto reach the solenoid valve in addition to the time it takes to move anarmature and corresponding valve component (after receiving theelectronic signal) to change an operating state of the solenoid valve.Many applications, especially those in internal combustion engines,require consistent switching times while operating throughout a varyingrange of operating parameters and conditions. One such operatingcondition variable is hydraulic fluid supply pressure that typicallyinterfaces with a solenoid valve component that is actuated to changethe operating state of the solenoid valve. Hydraulic fluid supplypressure can be a function of hydraulic fluid viscosity and temperature,along with hydraulic fluid pump speed. For an internal combustion enginethat operates within a wide temperature and engine speed range,significant supply pressure variation effects are possible. Referring toFIGS. 4A and 4B, the pressure-compensated solenoid valve 10 providesinternal pressure compensation by permitting hydraulic fluid to flowthrough the valve plunger 70 and armature 28 in an upward direction,providing an upper fluid force UFF to counteract an inherent lower fluidforce LFF that acts on the supply end 76 of the valve plunger 70 withinthe fluid supply port 84. The upper fluid force UFF is facilitatedby: 1) a first fluid flow path 72 arranged within the valve plunger 70;2) a second fluid flow path 30 arranged within the armature 28 which isfluidly connected to the first fluid flow path 72; and, 3) thecontainment tube 34 which encompasses the armature, forming a fluidcavity 33 between the containment tube 34 and an upper end 29 of thearmature 28. The containment tube 34 can be sealed by an axial seal 38.

The solenoid valve 10 described herein and captured in the Figures canprovide at least two basic functions. These two functions will bedescribed with an assumption that the solenoid valve 10 is utilizedwithin a variable valve train system capable of switching between twodiscrete valve lift modes; however, the solenoid valve 10 is alsocapable of being used in other types of systems. With this variablevalve train system example in mind, and view to FIGS. 5A-5C, the twofunctions include: 1) enabling and disabling fluid connection between apressurized fluid supply gallery 94 and an actuation fluid gallery 92;and, 2) maintaining a minimum hydraulic fluid pressure Pmin within theactuation fluid gallery 92 during a time when the fluid supply gallery94 is not fluidly connected to the actuation fluid gallery 92. Theminimum hydraulic fluid pressure Pmin typically ranges from 0.1 to 0.7bar, however, a higher minimum hydraulic fluid pressure Pmin is alsopossible. Function number two is needed to ensure that the actuationfluid gallery 92 is full of hydraulic fluid, as a full gallery of oil(with minimum air content) minimizes a time for communication ofpressurized hydraulic fluid to a receiving switchable valve traincomponent. An example of this type of variable valve train is capturedwithin U.S. Pat. No. 9,790,820, the entire contents of which areincorporated herein by reference.

Referring to FIGS. 2A through 6, the poppet 50 and its functionalattributes will now be described. The poppet 50 can be utilized tomaintain the previously described desired minimum hydraulic fluidpressure Pmin within the actuation fluid gallery 92 that is fluidlyconnected to the actuation port 82 of the solenoid valve 10. Maintainingthe desired minimum hydraulic fluid pressure Pmin is accomplished by thepoppet 50 serving as a pressure relief valve for the actuation fluidgallery 92, with the poppet 50 having a first closed position, and asecond open or pressure-relief position.

Referring to FIG. 5A, the valve plunger 70 is shown in a first seatedposition, and the poppet 50 is shown in the first closed position. Inthe first seated position of the valve plunger 70, a fluid supplygallery 94 is not fluidly connected to an actuation fluid gallery 92. Inthe first closed position of the poppet 50, the actuation fluid gallery92 is not fluidly connected to a tank gallery 90. The followingdiscussion describes pertinent features of these components relative tothe previously described functions of the solenoid valve 10.

The poppet 50 includes a through-passage 51, a first surface 54 at afirst end 52, and a second surface 58 at a second end 56. A portion ofthe valve plunger 70 extends through the through-passage 51. A biasspring retainer 62 is arranged within the through-passage 51; a lowerspring land 64 of the bias spring retainer 62 receives a bottom end of apoppet bias spring 46, with a portion of the poppet bias spring 46disposed with a lower spring well 60 of the poppet 50. The first surface54, or at least a portion thereof, together with the upper landingsurface 75 of the valve plunger 70 form a fluid access gap 57 that canbe accessed by hydraulic fluid when the poppet 50 is in the first closedposition. The fluid access gap 57, does not have to be a 360-degreecircumferential gap, as shown in the Figures; the fluid access gap 57could be one or more segments of circumferential gaps, such that the oneor more segments are less than 360 degrees. The first surface 54 of thepoppet 50 can define a first angled surface 55 having a first angle A1;and, the upper landing surface 75 of the valve plunger 70 can define athird angled surface 78 having a third angle A3. The first angle A1 canbe different than the third angle A3 to form the fluid access gap 57. InFIG. 5A, the actuation fluid gallery 92 contains a fluid F with a firstfluid pressure P1 that is less than or equal to the desired minimumhydraulic fluid pressure Pmin.

Now referring to FIG. 5B, the valve plunger 70 remains in its firstseated position as in FIG. 5A, however the poppet 50 is shown in thesecond pressure-relief position, displaced upward by the hydraulic fluidF having a second fluid pressure P2 that is greater than the desiredminimum hydraulic fluid pressure Pmin of the actuation fluid gallery 92.Initial upward displacement of the poppet 50 occurs when an inlet fluidforce IFF, a product of a second fluid pressure P2 within the actuationfluid gallery 92 and an area of a portion of the first surface 54 thatis exposed within the fluid access gap 57, exceeds a second biasingforce FS2 provided by the poppet bias spring 46. Therefore, the secondpressure-relief position can be any longitudinal position of the poppetat which the first surface 54 of the poppet is separated from the upperlanding surface 75 of the valve plunger 70. FIG. 5B shows the poppet 50at its upper-most stop position achieved when a fourth surface 66 of thepoppet 50 abuts with a fifth surface 68 of the sealing collar 42. Thesecond biasing force FS2 and the area of the portion of the firstsurface 54 that is exposed within the fluid access gap 57 should bedesigned such that the poppet moves upward when the second fluidpressure P2 exceeds the desired minimum hydraulic fluid pressure Pmin ofthe actuation fluid gallery 92. Stated otherwise, the second biasingforce FS2 and the area of the portion of the first surface 54 that isexposed within the fluid access gap 57 define a cracking pressure of thepoppet 50. With the poppet 50 in the second pressure relief position,the actuation fluid gallery 92 is fluidly connected to the tank gallery90 which has a pressure at or near atmospheric pressure PAT,facilitating a flow of the hydraulic fluid F from the actuation fluidgallery 92 to the tank gallery 90.

The poppet 50 accomplishes the pressure-relief or minimum pressuremaintaining task while incorporating features that provide fluid forcebalancing of the poppet 50. The second surface 58 of the poppet 50,together with the fifth surface 68 of the sealing collar 42 form a fluidexit passage 67 that exits hydraulic fluid to the tank port 80. Thesecond surface 58 can define a second angled surface 59 having a secondangle A2; and, the fifth surface 68 can define a fifth angled surface 69having a fifth angle A5. The previously described fluid access gap 57shown in FIG. 5A becomes a fluid inlet passage 61 upon upwarddisplacement of the poppet 50, as shown in FIG. 5B, to allow fluid toflow inside of the poppet 50. Now referring to FIGS. 8A and 8B, fluidforce balancing of the poppet 50 can be accomplished by adjustment ofone or both of the fluid inlet passage 61 and the fluid exit passage 67,such that the inlet fluid force IFF is balanced by the exit fluid forceEFF. The fluid access gap 57, and, thus, the resulting inlet fluid forceIFF, can be adjusted by changing the third angle A3 of the third angledsurface 78 of the valve plunger 70 or by changing the first angle A1 ofthe first angled surface 55 of the poppet 50. The fluid exit passage 67,and, thus, the resulting exit fluid force EFF, can be adjusted bychanging the second angle A2 of the second angled surface 59 or bychanging the fifth angle A5 of the fifth angled surface 69. All of theangles can be made larger or smaller, as shown in FIGS. 8A and 8B. Inaddition, the flow area can be made bigger or smaller by adjusting thedepths D1, D2 of the fluid inlet passage 61 and the fluid exit passage67, respectively. All of the aforementioned adjustments can be made tocontrol: 1) a fluid pressure differential between the fluid inletpassage 61 and fluid exit passage 67 (or stated otherwise, a pressuredrop across the poppet 50); and, 2) a fluid velocity of incominghydraulic fluid and exiting hydraulic fluid. Both these parameters(pressure differential/drop and fluid velocity) effect the magnitude ofthe inlet fluid force IFF and the exit fluid force EFF, and, thus, eachof these parameters can be tuned to achieve a balanced poppet 50.Without a balanced poppet 50 balanced by inlet and exit fluid forces,or, stated otherwise, without a poppet 50 that does not have a balancingexit fluid force EFF to counteract the inherent inlet fluid force IFF,the inlet fluid force IFF will contribute towards “de-seating” the valveplunger 70 while it is in the first seated position. Such a de-seatingforce can potentially lead to intermittent fluid communication of thefluid supply gallery 94 to the actuation fluid gallery 92 while thesolenoid valve 10 is functioning within a vibrating component, such asan internal combustion engine. Therefore, the solenoid valve 10 canachieve a fluidly balanced condition while the valve plunger 70 is inthe first seated position, and the poppet 50 at either of the firstclosed or second pressure-relief positions.

Referring to FIG. 5C, the second non-seated position of the valveplunger 70 is shown in which the fluid supply gallery 94 is fluidlyconnected to the actuation fluid gallery 92. In this state of thesolenoid valve, a third fluid pressure P3 of the hydraulic fluid F,higher than the second pressure P2, is present in the actuation fluidgallery 92. The third fluid pressure P3 can be capable of actuating acomponent, such as a switchable valve train component. With the valveplunger 70 in the second non-seated position, the poppet 50 is moved toits longitudinal stop position against the sealing collar 42, however,the fluid inlet passage 61 is closed due to the second non-seatedposition of the valve plunger 70, preventing fluid communication betweenthe actuation fluid gallery 92 and the tank gallery 90.

The exterior of the valve housing 44 can include radial seals, such asupper and lower seals 88A, 88B. These seals 88A, 88B and additionalseals can provide sealing isolation for the various ports arranged onthe valve housing 44. An optional filter 86 is arranged on the fluidsupply port 84 of the valve housing 44. A filter could also be placed onthe actuation port 82.

Referring to FIG. 7, a cross-sectional view of another exampleembodiment of a pressure compensated solenoid valve 10′ with fluid flowforce balancing is shown. The solenoid valve 10′ includes a bobbin 21′that houses a coil 26′, an armature 28′ that moves longitudinally withina containment tube 34′, a one-piece pole 36′, and a valve plunger 70′that moves longitudinally within the valve housing 44 to achieve thepreviously described first seated and second non-seated positions. Thevalve plunger 70′ includes a fluid aperture 79 arranged between theupper landing surface 75 and the lower seating surface 73. The fluidaperture 79 fluidly connects the fluid supply port 84 to the actuationport 82 of the solenoid valve 10′ while in either of the first seated orsecond non-seated positions.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms encompassed by the claims.The words used in the specification are words of description rather thanlimitation, and it is understood that various changes can be madewithout departing from the spirit and scope of the disclosure. Aspreviously described, the features of various embodiments can becombined to form further embodiments that may not be explicitlydescribed or illustrated. While various embodiments could have beendescribed as providing advantages or being preferred over otherembodiments or prior art implementations with respect to one or moredesired characteristics, those of ordinary skill in the art recognizethat one or more features or characteristics can be compromised toachieve desired overall system attributes, which depend on the specificapplication and implementation. These attributes can include, but arenot limited to cost, strength, durability, life cycle cost,marketability, appearance, packaging, size, serviceability, weight,manufacturability, ease of assembly, etc. As such, to the extent anyembodiments are described as less desirable than other embodiments orprior art implementations with respect to one or more characteristics,these embodiments are not outside the scope of the disclosure and can bedesirable for particular applications.

What we claim is:
 1. A solenoid valve comprising: a central axis; abobbin configured to support a coil; the coil configured to produce amagnetic field when energized with electric current; a pole, at least aportion circumferentially surrounded by the bobbin; a containment tube,at least a portion circumferentially surrounded by the pole; an armatureconfigured to be axially displaceable by the magnetic field, at least aportion of the armature circumferentially surrounded by the containmenttube; a valve plunger, axially displaceable within a valve housing to afirst seated position or a second non-seated position; a poppet arrangedto be axially displaceable within the valve housing to a first closedposition or a second pressure-relief position, the poppet biased to thefirst closed position by a poppet bias spring; and, the poppet arrangedwith a first surface at a first end and a second surface at a secondend, the first and second surfaces configured to equalize, respectively,an inlet fluid force acting on the poppet with an exiting fluid forceacting on the poppet, with the poppet in the second pressure-reliefposition.
 2. The solenoid valve of claim 1, wherein at least a portionof the valve plunger extends through a through-passage of the poppet. 3.The solenoid valve of claim 1, wherein the valve plunger is configuredwith a first fluid flow path and the armature is configured with asecond fluid flow path fluidly connected to the first fluid flow path,the first and second fluid flow paths arranged to transport hydraulicfluid from a supply end of the valve plunger to an upper end of thearmature, wherein a resultant upper fluid force acting on the upper endof the armature is balanced by a resultant lower fluid force acting onthe supply end of the valve plunger.
 4. The solenoid valve of claim 3,further comprising an armature bias spring arranged between the armatureand the containment tube, the armature bias spring urging the valveplunger to the first seated position.
 5. The solenoid valve of claim 4,wherein at least a portion of the armature bias spring is received by aspring bore arranged on an upper end of the armature.
 6. The solenoidvalve of claim 1, wherein the first seated position of the valve plungercorresponds with a de-energized state of the coil, and the secondnon-seated position of the valve plunger corresponds with an energizedstate of the coil.
 7. The solenoid valve of claim 1, wherein in thefirst seated position, an actuation port of the solenoid valve is notfluidly connected to a fluid supply port of the solenoid valve, and inthe second non-seated position, the actuation port of the solenoid valveis fluidly connected to the fluid supply port of the solenoid valve. 8.The solenoid valve of claim 1, wherein in the first closed position ofthe poppet, the poppet engages an upper landing surface of the valveplunger.
 9. The solenoid valve of claim 8, wherein the first surface andthe upper landing surface form a fluid access gap, the fluid access gapconfigured to receive a fluid.
 10. The solenoid valve of claim 9,wherein the poppet is configured to be axially displaceable by the fluidwithin the fluid access gap.
 11. The solenoid valve of claim 8, whereinthe upper landing surface defines a third angled surface having a thirdangle.
 12. The solenoid valve of claim 11, wherein the first surface ofthe poppet defines a first angled surface having a first angle, thefirst angle different than the third angle, the first angled surface andthe third angled surface a forming a fluid access gap.
 13. The solenoidvalve of claim 1, further comprising a sealing collar arranged withinthe valve housing, at least a portion of the valve plunger extendingthrough the sealing collar, wherein the sealing collar forms an fluidexit passage with the poppet.
 14. The solenoid valve of claim 13,wherein the sealing collar is configured as a longitudinal stop for thepoppet in the second pressure-relief position.
 15. The solenoid valve ofclaim 13, wherein the sealing collar is configured with an upper springwell that receives at least a portion of the poppet bias spring.
 16. Thesolenoid valve of claim 1, wherein the poppet bias spring and at least aportion of the first surface cooperate to define a cracking pressure ofthe poppet.
 17. The solenoid valve of claim 1, wherein the secondpressure-relief position of the poppet is configured to fluidly connectan actuation port of the solenoid valve to a tank port of the solenoidvalve.
 18. The solenoid valve of claim 1, wherein the poppet isconfigured with a lower spring well to receive at least a portion of thepoppet bias spring.
 19. The solenoid valve of claim 1, wherein the valveplunger includes a fluid aperture configured to fluidly connect a fluidsupply port of the solenoid valve to an actuation port of the solenoidvalve while in the first seated position or the second non-seatedposition.
 20. A solenoid valve comprising: a central axis; a bobbinconfigured to support a coil; the coil configured to produce a magneticfield when energized with electric current; a pole, at least a portioncircumferentially surrounded by the bobbin; a containment tube, at leasta portion circumferentially surrounded by the pole; an armatureconfigured to be axially displaceable by the magnetic field, at least aportion circumferentially surrounded by the containment tube; a valveplunger, axially displaceable within a valve housing to a first seatedposition or a second non-seated position; a poppet arranged to beaxially displaceable within the valve housing to a first closed positionor a second pressure-relief position, the poppet biased to the firstclosed position by a poppet bias spring; and, the poppet configured tobe engaged at a first angled end by an inlet fluid producing an inletfluid force, and at a second angled end by an exiting fluid producing anexiting fluid force, the poppet balanced by the inlet fluid force andthe exiting fluid force in the second pressure-relief position.